The right of priority under 35 U.S.C. xc2xa7119(a) is claimed based on German Patent Application No. 101 28 164.1, filed Jun. 9, 2001, the entire disclosure of which is hereby incorporated by reference.
The invention relates to a vehicle cooling system for a temperature-raising device, especially a drive battery or fuel cell, preferably for an electric or hybrid vehicle. The system employs a coolant that cools the device in cooperation with the air-conditioning system that serves for air-conditioning the passenger compartment of the vehicle.
In known production hybrid vehicles the drive battery (which constitutes a temperature-raising device) is cooled by air flowing through it. Since on hot days the outdoor air temperature exceeds 30xc2x0 C., in such cases it is not the ambient air that is used to cool the battery but air from the passenger compartment. Although this air originates from outside the vehicle, it has been cooled and if necessary dried by an air-conditioning system before flowing into the passenger compartment. This known air cooling concept has the disadvantage that the battery cooling capacity is heavily dependent on the air temperature in the passenger compartment. Thus, over short distances, the air temperature in the passenger compartment may far exceed the 30xc2x0 C. required as a minimum. Furthermore, the passenger compartment temperature is dependent upon the subjective perception of the vehicle occupants. If adequate cooling of the battery is not possible, the hybrid drive will no longer be able to provide the vehicle with full drive power. Moreover, a relatively poor heat transmission takes place between the cooling air and the battery, so that only correspondingly low thermal loads can be dissipated. Operating situations are therefore possible, in which the thermal load actually dissipated is more than 70% below the thermal load to be dissipated.
One object of the present invention is to provide an improved cooling system for a temperature-raising device, especially a drive battery or fuel cell, preferably for an electric or hybrid vehicle.
A specific object of the invention is to create a vehicle cooling system of the aforementioned type, in which significantly greater amounts of heat can be dissipated. It is intended, in particular, that the air temperature in the passenger compartment should exert extremely little, if any influence.
A further object of the invention is to provide a method for cooling a temperature-raising device in a vehicle.
Still another object of the invention is to provide an improved vehicle of the type having a temperature-raising device comprising a drive battery and/or a fuel cell as part of the propulsion unit for the vehicle.
In accordance with one aspect of the present invention, there has been provided a cooling system for a temperature-raising device of a vehicle having an air-conditioning system that serves for air-conditioning of the passenger compartment of the vehicle and that includes a refrigeration circuit. The cooling system comprises a cooling circuit for cooling the temperature-raising device, wherein the cooling circuit is designed for circulating a liquid coolant for cooling the temperature-raising device and is thermally integrated into the refrigeration circuit of the air-conditioning system.
In accordance with another aspect of the invention, there is provided a method for cooling a temperature-raising device in a vehicle having a passenger compartment, comprising: cooling the vehicle device by a circulated liquid coolant; and directly exchanging heat between the coolant and a refrigerant of an air-conditioning system serving for air-conditioning the passenger compartment of the vehicle.
In accordance with still another aspect of the invention, there has been provided a vehicle, comprising: a temperature-raising device comprising at least one of a drive battery and a fuel cell as part of the propulsion unit for the vehicle; an air-conditioning system that serves for air-conditioning the passenger compartment of the vehicle and that includes a refrigeration circuit; and a cooling system for the temperature-raising device of the comprising a cooling circuit as defined above.
Further objects, features and advantages of the present invention will become apparent from the detailed description of preferred embodiments that follows, when considered together with the accompanying figures of drawing.